SSI doesn't work with servlets

Hi, I've got a problem with running servlets with SSI. I've tried it
with the <servlet></servlet> tags and with the <!--#servlet 
name="servletname" code="/servlet/servletname" --> command in .shtml 
files, but there's no output. When I type the /servlet/servletname in 
the browser the servlet is normally executed, so the servlet is not the 
problem. Does anybody knows what the problem is? Do you have to 
configure the servlets manually?

greetings Paul